Studies performed were aimed at determining the host's immune response to tissues placed in the anterior chamber of the eye and the brain. Skin implants placed in the anterior chamber of the eye of rats reduce the host's ability to reject skin grafts from a donor syngeneic with the donor of the implant tissue. This rejection reaction is delayed in spite of a positive MIF response in the host. Other studies have shown that lymphocytes from implant recipients have a reduced capacity to produce the local graft versus host reaction. It appears that the host can recognize tissues placed in the anterior chamber of the eye but the host's ability to complete rejection is delayed. This phenomenon is probably due to the production of suppressor cells or blocking factors. Preliminary studies using implants of skin in the rat brain indicate that the host responds to this tissue in a similar manner. BIBLIOGRAPHIC REFERENCES: Vessella, R. L., Grogan, J. B., Raju, S., and Cockrell, J. V.: The anterior chamber of the eye: A sensitive site for the detection of cross-reacting alloantigens. J. Surg. Res., 22:1, 1977. Raju, S., Vessella, R. L., Cockrell, J. V., and Grogan, J. B.: Accelerated rejection of specific and third party alloimplants in the anterior chamber of sensitized rats. Clin. Res., 25:55A, 1977 (abstract).